Electromagnetic device



p 1932- H. F. OBERGFELL ELECTROMAGNETIC DEVICE Filed Dec. 14. 1931 all15m Herb EFT F. U]: E1-

Patented Sept. 20, 1932 UNITED STATES PATENT OFFICE HERBERT F.OBERGFELL, OF RIVER FOREST, ILLINOIS; ASSIGNOR, BY MESNE ASSIGN- MENTS,T0 ASSOCIATED ELECTRIC LABORATORIES, INC., OF CHICAGO, ILLINOIS, A :1

CORPORATION OF DELAWARE nmcmoimennrre nnv'rcn Application filed December14, 1931. I Serial No. 580,895.

This invention relates to electromagnetic devices in general, but moreparticularly to electromagnetic devices such as induction coils and theprincipal object of the inven- 5 tion resides in the provision of a newand improved type of induction coil in which the spool heads of the coilare formed of moulded material which serves to support the coil as aunit and at the same time constitute terminal blocks for extendingconnections to the windings of the coil or for connections to otherapparatus.

A further object of the invention resides in means in the combined spoolheads and ter- 5 minal blocks for protecting and segregating the variousconducting wires extending from the windings of the coil to the terminalconnections on the spool head.

Further objects of the invention are concerned with the design of a newand improved induction coil which is economical to manufacture, iscompact and sturdy in structure and presents a number of desirableadvantages over previous types of induction coils.

It has been the practice, in the past, to

construct induction coils or electromagnetic devices with the windingsof the coils wound directly around a laminated core and with a circularor disc shaped insulated spool head forced over each end of the core tohold the windings in place. With this type of structure it will beeasily seen that'with rough handling, temperature changes or othercauses, the structure of the coil is easily dam- 35 aged, the windingsbroken and the spool heads broken ofi resulting in an inoperative ordefective coil which must be replaced or repaired. Similarly noprovisions were made for protecting or supporting the short connectingleads extending to the windings. It was common practice to connect thesedirectly to a separate terminal block mounted adjacent the inductioncoil and this structure therefore necessitated the utilization ofconsiderable valuable space when the device is 'tion of the core 4.These ends 5 and 8 are incorporated, for example, in a telephonesubstation apparatus. By providing a device according to the inventionthe above difficulties and objectionable features are obviated.

The invention is disclosed in the accompanying drawing in which Fig. 1shows a top view of the preferred embodiment of the invention. Fig. 2 isa side elevation partly in section; while Fig. 3 shows a perspectiveview of the device with the windings removed.

The induction coil, according to the invention, comprises primarily alaminated core 4, the opposite ends 5 and 8 of which are bent downwardat right angles to the main pormoulded directly into the combinationspool heads and terminal blocks 68 and 7. These blocks 6 and 7 may beformed of insulation material such as a phenolic condensation productknown to the trade as bakelite. Bybeing poured into a mould in which thelaminated core 4 is placed a rigid. sturdy, and compact structureresults which can be of any desired shape and configuration, and due tothe extension pieces 5 and 8 the blocks 6 and 7 will be prevented frombeing twisted and turned and separated from the core. The various coilwindings 9 are wound directly upon and suitably insulated from the core4 between the blocks 6 and 7 and as is well known, these induction coilsmay have several separate anddistinct windings so that a plurality ofterminals must be provided for the connecting leads. By providing astructure in which the spool heads 6 and 7 are moulded directly upon thecore 4 a structure is provided which will not be affected by moisture orother climatic conditions. Fiirthermore, the need for providing separatefastening means for holding together the plurality of separatelaminations of the core 4 is obviated. I

In order to provide a means for mounting and supporting the coil as aunit the screw 90 holes 10 in block 6 and 11 in block 7 are provided.

The terminal portion of the blocks 6 and 7 provides a means foraccommodating the terminal screws, such as 12, 13, 14 and 15 for examplein block 6; similar screws being provided in the block 7. The terminals12, 13 and 15 are provided with soldering tags 17 to which the variousconnecting leads extending from the windings of the induction coil areconnected. The soldering tags 17, as clearly shown in Fig. 2, areriveted to brass studs 18 which are moulded directly into the insulatedblock. These brass studs 18 are tapped to receive the terminal screws.

Any number of soldering lugs and associated terminal screws may beprovided. If it is desired however not to provide a soldering tag 17 thestud 16 is only provided and the screw such as 1 1 in block 6 isthreaded into stud 16 and serves as a distributing point for apparatusother than the windings of the coil.

Projecting upwardly from theblock 6-, for example, and extending inclose proximity to the terminal posts 12 and 13 are a series ofprotuberances or extensions 20 which are moulded integral with theblock. Similar project-ions 21 surround the screw terminals 1 1 and 15as is clearly shown in Fig. 3. The purpose of these projections aroundeach terminal is to provide a means for securely holding and locking thespade terminal clips to which the connecting wires are attached, to theblock. In placing the spade clips in position, the screw terminal 12 forexample is loosened a sufiicient distance out of the stud 18, so thatthe spade clip can he slipped under the head after which the screw canbe turned down on top of the clip. In case it should occur that thescrews become slightly loosened upwhile the device is in use, it will beclearly seen that the projections 20 and 21 will prevent the-spade clipsfrom completely pulling away from their associated terminal posts,thereby lessening the chances of causing any disconnection of thecircuits to which the induction coil is connected.

In case it is desired, any number of additional spade clips and theirassociated connecting leads may be attached to the same terminal posts.By placing suitable extension studs on the mounting bolts provided inthe holes 10 and 11, additional terminal posts may be provided so thatother spade clips may be attached thereto and locked in position on theprojections 26 and 27 formed in the blocks 6 and 7 respectively. The terminal posts 12, 13, 14 and 15 may likewise serve as supporting orholding means for additional apparatus such as, for example, condensers,buzzers, etc. in additioncto serving as terminal posts for theconnecting leads.

The connecting leads 30 from the windings of the coil 9 which aresoldered to the sol dering tags 17 are arranged to lie in the slots 25separated by projections 24 so there will be no danger of causing ashort circuit or crossover between them. The slots 25, as is clearlyseen in the block 7 of Fig. 3, are situated so that the connecting leads30 are enabled to extend directly outwards from the winding of theirrespective coils. The reason for this is that as additional layers ofwindings are placed on top of one another there will be no danger ofshearing, crushing or breaking the connecting leads and no specialprovisions for protecting these connecting leads are necessary as was inthe prior types of induction coils. The slots 25 are. cut into the spoolhead slightly and extend upward to a point on about the level of theends of the soldering tags 17. F urthermore, due to the fact that theblocks 6 and 7 are inherently constructed of insulating material nospecial provisions are required for insulating the connecting leads andbare wire conductors may be used, in which case it may be desirable tofill up the hollow space in which the conductors lie in each block withsome suitable insulating compound.

lVhat is claimed is:

1. In an electromagnetic device, a laminated core, a combination spoolhead and terminal block moulded on each end of said core, each end ofthe core having a portion extending at an angle therefrom in the blockfor securely holding said blocks inspaced relationship on said core.

2. In an electromagnetic device, a laminated core having a downwardlyprojecting portion extending from each end thereof, a spool head mouldedon each end of said core around said projections and held in positionthereby, terminal means moulded in the top of said spool head forattachment of connecting wires, and means in the spool heads forsupporting said device as a unit.

3. In an electromagnetic device, a laminated core having a projectionformed on each end thereof, a combination spool head and terminal blockformed around each of said projections, said blocks securely bindingtogether the laminations of said core, and a plurality of terminal studsmoulded directly into the top of said blocks.

4. An electromagnet comprising a core made up of a plurality oflaminations, the ends of the core being bent at an angle, spool headssupported on each end of the core, said spool heads binding togethersaid lamina tions, the angular ends of the core preventing displacementand turning movement of the spool heads, and a plurality of terminalsmounted directly on top of said spool heads on the opposite side fromthe angular end of the core.

5. An electromagnet comprising a core and windings, each end of the corebeing bent downward at an an le, spool heads moulded on each end of theent portion of the core, said bent portions preventing displacement ofthe spool heads, terminal posts mounted on the top of said spool headson the opposite end from the downward portions of the core, and aplurality of slots formed in the side of each spool head to protect andinsulate the conducting wires extending from the windings of the coil tothe terminal posts.

In witness whereof, I hereunto subscribe my name this 11th day ofDecember, A. D.

HERBERT F. OBERGFELL.

